In the past manipulation, threading and circulation of casing or tubulars was done with a variety of tools such as fill up and circulation tools that featured a seal to the inside or the outside of the tubular to be able to pump fluid as the tubular string was lowered into the borehole or to initially fill that last segment that was added to the string before running in. Typically the handling of a joint to be added to a string was done with elevators and the threading was accomplished with tongs. Such tools are illustrated in U.S. Pat. Nos. 6,578,632; 5,971,079; 7,028,769; 7,065,515 and 6,173,777.
More recently systems have been developed that employ the top drive for rotation and axial movement of a tubular joint to be made up to an existing string and advanced into the borehole. These are rather complex devices that rely on cam pairs to convert rotation to axial movement of slips that cams the slips radially outwardly or inwardly to grip the inside or the outside of a tubular. They feature opposed cam pairs to allow slip actuation with bi-directional rotation and a lock position in between to allow for release. These designs are highly complex and expensive to produce and present complications that could require significant downtime for maintenance. The design is illustrated in in U.S. Pat. Nos. 8,424,939 and 7,909,120.
In a first embodiment of the present invention enables selective grip and release of a tubular joint to thread a connection and to rotate a string while facilitating release to get the next joint in the string connected. The device may include a lower end seal preferably in the form of a cup seal and slips in a housing that respond to axial movement of an actuating member. The actuating member is connected to a clutched drive that is engaged for power delivery and disengaged with set down weight from the top drive. Drive rotation turns a thread that is engaged to the actuating member to move the actuating member axially in one of two opposed direction for radial extension or retraction of the slip segments. With the slips engaged the string can be rotated while lowered or lifted. With the string supported from the rig floor the top drive can radially allow the slips to retract with rotation. Those skilled in the art will have a better understanding of the present invention from the description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be found in the appended claims.
In an alternative embodiment the components are rotationally locked to the housing of the tool as it is inserted into the casing as well as when weight is set down after the slips are extended to grab the casing. In between is a position that allows one or more parts to be rotated that engage with another part that is limited to axial movement so that a multi-ramped mandrel extends the slips to grip. When the slips are set with the needed torque the relatively rotating components are rotationally locked to the housing such that top drive rotation of the housing will turn the string rather than further trying to extend the slips, this avoiding potential damage to the casing from slip overextension.